NTA guidelines says you need to pass 12 with pcb for eligibility of NEET. So its okay to repeat 12 with pcmb to write neet. Its not necessary to repeat 11th with pcmb. You need to upload marksheet of  12th only. But you need to study all those 11th biology topics to crack NEET. There are 22 chapters in 11th and all are very important chapters for NEET. So you are eligible to write the exam even though you didn't study biology in 11th. But you need to study all those topics to score well.